In a wireless communication system, a receiver often has to generate an estimate corresponding to a signal received from a transmitter prior to performing decoding. Along with the signal estimate, additional parameters that affect the decoding based on the estimate may also have to be computed. Typically, these parameters are used to soft/hard decode the estimates and are sometimes referred to as slicing parameters.
Various aspects of the signal processing are generally done in the physical layer of the receiver using fixed point arithmetic. In fixed point arithmetic, each of the quantities are represented using a finite number of bits. It is highly desirable to have low complexity with regard to the fixed point processing, e.g., to allow for lower cost implementations, faster processing, and/or lower power consumption. Division by numbers that are powers of two can be implemented using low complexity shift operations. However, division by numbers that are not powers of two increases the complexity of the implementation. It would be advantageous if methods and apparatus were developed which could avoid or reduce the number of non-shift based division operations so as to reduce complexity.
In systems where a receiver is attempting to recover transmitted symbols corresponding to two different transmission streams, the number of fixed point computations in the symbol estimation processing is typically significantly higher than when attempting to just recover symbols corresponding to a single transmission stream. Thus in such a situation it would be highly beneficial if methods and apparatus that reduced computational complexity were implemented.
Based on the above discussion there is a need for methods and apparatus that reduce or completely eliminate non shift based divisions while estimating transmitted symbols and/or slicing parameters corresponding to multiple, e.g., two, symbol transmission streams.